Draft sintering apparatus



March 12, 1940. -o. ROLFSEN 2,193,698

DRAFT SINTERING APPARATUS Filed Oct. 3, 1939 2 Sheets-Sheet 1 o/wmw March 12, 1940. o. ROLFSEN Y 2,193,698

DRAFT SINTERING APPARATUS Filed 001;. 5, 1939 2 Sheets-Sheet 2 Patented Mar. 12, 1940 UNITED STATES PATENT OFFICE Application October 3, 1939, Serial No. 297,757 In Germany March 29, 1939 8 Claims.

The present invention has for its. object a rotating draft sintering apparatus which is particularly adapted for the sintering of cement as well as for the sintering of other granulated material, such as ores or the like.

An important feature of the invention consists therein, that the sintering apparatus comprises a truncated cone rotating about an inclined axis, the sintering surface being formed by the exterial conical surface thereof.

The axes of the rectilinear grate bars substantially form describing lines of the conical surface, however, whenthe grate bars have a uniform cross section, they are located alternately on two co-axial conical surfaces with different apex angles, intersecting each other adjacent the exterior ends of the grate bars.

The apex angles of the said two conical surfaces may be so chosen that the slots between the grate bars will have substantially uniform width, whereas the staggered position of the grate bars will also have the effect of preventing the material to be sintered from slipping off the sintering grate at an early stage during the rotation of the apparatus.

Preferably the conical surface forming the grate surface has an apex angle of approximately 90, whereas the angle of inclination of the axis of rotation is approximately 45. Hereby it is obtained that the grate surface will be approximately horizontal in its upper, and approximately vertical in its lower position, and experiments have proved that under these circumstances at least the upper third or more of the grate surface may be utilized for carrying out the draft sintering process.

The space inside the grate surface is divided in chambers which are adapted to be connected, by means of controlled valves, with a central suction conduit, whereby the draft of air through the sintering material may be controlled in accordance with the requirements of the process.

Generally it is preferred to make the grate bars in the form of water-cooled tubes, the tubes having their exterior open ends located in an annular water supply chamber, and their inner open ends located in a chamber for the outlet of water.

Owing to the increasing inclination of the tubes during the movement from the upper to the lower position, it is then obtained that the current of cooling water through'the tubes is increased by thermosiphonic action, and this is particularly the case with the tubes which are exposed to the highest temperatures.

' shaped comb rail l9, so that the suction valves On the drawings a form of the invention is illustrated, Figure 1 being an axial section, whereas Figure 2 is a sectional View. from the right-hand side on the broken line II--II of Figure 1. Figure 3 is a detail section on the line IIIIII, and Figure 4 is another detail section on the line IV-IV of Figure 1.

As seen in Figure l, the apparatus comprises a truncated cone, the exterior surface l of which is formed by the grate surface. The apex angle of the conical surface is approximately 90, and the apparatus rotates about an axis which is inclined approximately 45. The truncated cone is attached to a cylindrical centre piece 2 which is rotatably supported at 3 and 4. The rotation is caused by a motor 5 over a helical and ordinary gearing (6 and l) the pinion 1 engaging a toothed ring 8.

The grate bars I, forming the exterior surface of the truncated cone, are bordered on their inner and outer ends by annular ribs 9, III, which are substantially perpendicular to the surface of the truncated cone, so that there is formed an open channel having a conical bottom formed by the grate bars.

In order to obtain air slots with uniform width, when grate bars of uniform cross section are used, the grate bars are alternately arranged with different inclination, so that the inner ends of the grate bars, as seen in Figure 3, lie on circles with different diameters.

This may also be expressed differently by stating that the grate bars alternately have their axes on two co-axial conical surfaces having different apex angles and intersecting each other near the exterior ends of the grate bars.

Inside the grate surface there is a closed annular chamber II which is divided by means of radial walls l2 (see Figure 2) in separate chambers, which communicate through valve controlled outlet openings l3 with the interior chamber H and further with the air suction pipe I5.

The suction valves are actuated by means of spring actuated cranks H, the free ends of which carry rollers l8, co-operating with a suitably are opened when the corresponding chambers approach the upper position, such as is for instance the case with the chamber I4 in Figure 2.

The cooling of the tubular grate bars is effected by means of water which is conducted through pipe 20 into chamber 2|, from which it passes through pipes 22 to the annular water supply chamber 23, with which tubes I communicate at their exterior ends.

After the cooling water has passed through tubes I it arrives into chamber 24 and is let out through the upper part of cylinder 2.

Dust collecting in the interior of suction chamber I4 is removed through pipe 21 which is provided with the lock valves 25, 26.

When the apparatus here described is used for carrying out a draft sintering process, the material to be sintered and the necessary combustible are applied to the grate surface by means of a suitable continuously working conveyer, the point of application of the material being some distance before the highest point of the grate surface. The ignition takes place immediately after the material has been placed on the grate surface.

The sintering process is then completed during the subsequent third of the revolution, or there about, and the sintered material is finally removed from the grate surface at some place near the lowest part thereof, either by gravity alone or by means of a suitable scraper, or the like.

I claim:

1. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis.

2. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, the apex angle of said truncated cone and the angle of inclination of its axis being approximately 90 and 45 respectively.

3. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, the grate bars being substantially rectilinear and approximately forming describing lines of the conical surface.

4. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, the grate bars being substantially rectilinear and forming describing lines of two conical surfaces having different apex angles and intersecting each other adjacent the exterior ends of the said grate bars.

5. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, the grate bars being in the form of rectilinear watercooled tubes, the axes of which form describing lines of two conical surfaces having different apex angles and intersecting each other adjacent the exterior ends of the said grate bars.

6. A draft sintering apparatus in which the grate surface is formed by the exterior surface ,of a truncated cone rotating about its axis, the

grate bars being in the form of rectilinear watercooled tubes, the axes of which form describing lines of two conical surfaces having different apex angles and intersecting each other adjacent the exterior ends of the said grate bars, said tubes communicating with their exterior open ends with an annular water supply chamber and with their interior open ends with an outlet chamber for cooling liquid.

7. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, said surface being bordered on both sides by annular ribs substantially perpendicular to the grate surface so as to form a channel for receiving the material to be sintered.

8. A draft sintering apparatus in which the grate surface is formed by the exterior surface of a truncated cone rotating about its axis, the space inside said grate surface comprising an annular chamber divided in separate sections by means of radial walls, each separate section being provided with a controlled suction valve, by means of which it is connected with an interior suction chamber, in accordance with the requirements of the process.

OLE ROLFSEN. 

